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ur struggle for survival has always entailed a
battle against the countless microbes with which we share the
earth. Hostile bacteria, viruses, fungi, and parasites invade our
bodies and go to war with our immune systems. To fight back, we
must call forth all our strength and defenses. Plagues and
epidemics are as much a part of our history as any struggle
between nations.
Though it may seem hard to believe, prior to the
use of penicillin during World War II, physicians had no
effective medicines to treat serious infections. Fifty years
later, we have more than 100 different antibiotics--including
sulfa drugs, synthetic penicillin, and many, many more--to ward
off the full spectrum of bacterial diseases. The development of
numerous vaccines has virtually wiped out many former killers,
both bacterial and viral, in the U.S. and many other developed
countries.
Yet infection still plagues us, despite these
gains. Many strains of bacteria are now resistant to the drugs
that once killed them. Most viruses are impervious to antiviral
drugs. Some microorganisms come in so many different forms that a
single vaccine just can't cope with them all. Other
microorganisms elude treatment by hiding in hard to reach areas
such as the central nervous system and bones. Then too, some
people today are simply exposed to a wider range of diseases
because of our increased mobility, the use of immunosuppressive
drugs, and such invasive procedures as surgery and
catheterization.
Consequently, infection is still a serious threat,
even in our highly advanced society. In Third World countries,
infectious diseases continue to cause widespread mortality.
How Infections Cause
Illness
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When organisms invade the body, they reproduce and
multiply rapidly. In the process, the microorganisms compete with
the body's metabolic processes. Some also produce toxins that
injure cells. What's more, our own immune response may actually
cause even further tissue damage. How sick someone actually gets
as a result of the infectious process depends on the type and
number of invading organisms and the person's overall health and
strength.
Staph
Infections
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Staphylococcal bacteria produce a wide range of
diseases, causing anything from skin eruptions to blood poisoning
(bacteremia) and death. Staphylococcal infections include the
following conditions:
Bacteremia , the presence of bacteria in
the blood, is characterized by a high fever, shaking chills,
racing heart, pallor, agitation, and joint pain. It may progress
to confusion and stupor, and can be fatal in just 12 hours.
Treatment must begin immediately with semisynthetic penicillin
(nafcillin or methicillin) or cephalosporins (cefazolin) given
intravenously. People who are allergic to penicillin or are
infected by penicillin-resistant organisms must be treated with
vancomycin.
The symptoms of staphylococcal pneumonia
are similar to those of other pneumonias--sudden onset of high
fever, cough with yellow or bloody sputum, difficulty in
breathing, and chest pain. Treatment consists of the same
medication used for bacteremia.
The use of some of these drugs, particularly
broad-spectrum antibiotics like cephalosporins, sometimes brings
on enterocolitis (inflammation of the intestines). This condition
is marked by profuse, watery diarrhea; abdominal pain; nausea;
vomiting; and dehydration. If a patient develops enterocolitis,
the antibiotics must be stopped at once and replaced with a
different drug, such as vancomycin.
Osteomyelitis is a bone infection that
occurs as a complication of a blood-borne infection, or as a
sequel of surgery or trauma. Osteomyelitis may come on rapidly,
exhibiting fever, sudden pain, swelling, tenderness, heat, and
restricted movement in the affected bone. Its onset can also be
insidious, however, with fever as the first warning. Treatment
consists of surgery to open and cleanse the wound and large doses
of antibiotics for four to eight weeks.
Staphylococcal bacteria are among the most common
causes of food poisoning. Symptoms of food poisoning
include nausea, loss of appetite, diarrhea, vomiting, and
abdominal cramps. Since the symptoms typically subside within 18
hours, there's usually no need for treatment unless the person
shows signs of dehydration. Full recovery takes one to three
days.
Some skin infections owe their source to
staphylococcal bacteria as well. These infections are manifested
by widespread inflammation of soft tissue (cellulitis), and
pus-producing or boil-like lesions, sometimes accompanied by
fever and discomfort. Treatment includes applying mupirocin
ointment (Bactroban), as well as administering oral antibiotics
(erythromycin, dicloxacillin, or cloxacillin). Severe infections
are treated with intravenous oxacillin, methicillin, or
nafcillin. Ointments such as bacitracin-neomycin-polymyxin are
used to prevent further infection of broken
skin.
Toxic shock syndrome (TSS) is an acute
infection that is sometimes associated with tampon use during
menstruation. The symptoms of toxic shock syndrome include a high
fever, an abrupt episode of shivering and chills, intense muscle
pain, profuse watery diarrhea, headache, and vomiting. A dark red
rash appears on the palms and soles within a few hours. Shock may
develop within 48 hours.
TSS is treated with antibiotics, such as
oxacillin, methicillin, and nafcillin, given intravenously.
Strep
Infections
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A total of 21 species of streptococcal
bacteria have been identified, but three classes--Groups
A, B, and D--are responsible for most
infections.
Group A bacteria cause the following
infections:
Streptococcal pharyngitis accounts for the
majority of sore throats caused by bacteria. Children between the
ages of five and 10 years get most of these strep throats--mainly
from October through April. The symptoms of strep throat may
include a fever, severe pain and difficulty swallowing, inflamed
tonsils, a sore and red throat, a "strawberry'' appearance of the
tongue, enlarged lymph nodes, loss of appetite, weakness,
malaise, and abdominal discomfort.
Sometimes, however, the symptoms of strep throat
are mild, and the infection escapes detection. Left untreated, a
strep infection can lead to rheumatic
fever.
It is essential that anyone with a strep throat
take the full prescription of antibiotics--usually either
penicillin or erythromycin. Isolation from others for 24 hours
after starting antibiotic therapy is recommended to prevent the
disease from spreading.
Scarlet fever may occur along with a strep
throat, certain wound infections, and blood poisoning. Children
between the ages of two and 10 years are most likely to get
scarlet fever. Symptoms include those of strep throat plus a
sunburn-like rash that feels like sandpaper to the touch. The
rash usually begins on the upper chest and then spreads to the
rest of the body. Prompt treatment with an antibiotic is
essential.
Erysipelas is another type of strep
infection. It usually occurs in infants and in adults over 30
years of age. When erysipelas develops, swollen, red, raised
lesions with a raised, firm border suddenly appear and spread.
Other symptoms include headache, vomiting, fever, and
irritability. An antibiotic should be administered promptly. Cold
packs and analgesics, such as aspirin and codeine, can alleviate
local pain.
Other infections caused by streptococcal A
bacteria include impetigo (skin lesions with itching and
encrustment) and lymphadenitis (red-streaked, painful skin
lesions with fever, racing heart, and lethargy.) Both infections
require treatment with antibiotics.
Group B streptococcal infections include
newborn and adult forms. The adult form usually occurs after
women give birth. Both newborn and adult infections are usually
treated by penicillin or ampicillin. Group D streptococcal
bacteria are frequently implicated in endocarditis, an
inflammation of the interior of the
heart.
Various strains of strep are among the causes of
other diseases, including pneumonia (see Chapter 6 on
respiratory disorders); otitis media (fluid in the middle
ear); and meningitis. All of these infections are treated
with penicillin, amoxicillin, or ampicillin.
Meningitis
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Meningitis occurs most often in children under
five years of age and in people living in crowded conditions such
as those found in the military or in institutions. In older
patients, meningococcal bacteria are a more likely cause than
strep. The symptoms are varied and may include sore throat; stiff
neck; a sudden, spiking fever; intense headache; chills; muscle
pain in the back and legs; racing heart; and a rash. As many as
20 percent of all cases evolve into a severe form of meningitis
marked by extreme prostration, intravascular coagulation, skin
lesions, and shock. Left untreated, this particular infection may
cause respiratory or heart failure and be fatal in just six to 24
hours.
Meningitis must be treated immediately with large
doses of penicillin G, ampicillin, or a cephalosporin, such as
ceftriaxone or cefotaxime.
Tetanus
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People get tetanus (lockjaw) when a puncture wound
becomes contaminated by soil, dust, or animal feces. The
incubation period ranges from less than two days in severe cases
to three or four weeks in milder cases.
Symptoms include spasms and increased muscle tone
near the wound, profuse sweating, and a low-grade fever. Patients
also experience an extreme tightening of neck and facial muscles,
which produces a grotesque grinning expression; rigidity of
abdominal and back muscles; and
convulsions.
Treatment must begin within 72 hours after a
puncture wound occurs. Patients who have no previous immunization
need tetanus immune globulin or tetanus antitoxin for temporary
protection, followed by immunization with tetanus toxoid. Those
who have not been immunized in the past five years need a booster
shot of tetanus toxoid. If tetanus develops, treatment consists
of airway maintenance and the use of muscle relaxants, such as
diazepam (Valium), or a neuromuscular blocker. High doses of
antibiotics (preferably penicillin) are also necessary.
Intestinal
Infections
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Salmonella is an extremely common infection--more
than two million new cases are reported in the United States each
year. Salmonella bacteria are the cause of typhoid fever, and are
often the culprits in gastroenteritis (inflammation of the
stomach and intestines). Occasionally, they cause blood poisoning
and localized infection.
Gastroenteritis caused by salmonella is usually
contracted by eating contaminated or inadequately processed
foods--especially eggs, turkey, duck, and chicken. Other sources
include contaminated dry milk, chocolate bars, and contact with
infected animals or people. Symptoms typically include diarrhea,
nausea, abdominal pain, and fever. Though the infection usually
clears up on its own, at times it may progress to intervals of
high fever, abscesses, dehydration, and blood poisoning.
Treatment for uncomplicated cases includes bed rest and fluid and
electrolyte replacement.
Typhoid fever is usually contracted by drinking
contaminated water, takes three weeks to run its course, and is
marked by persistent fever and flu-like symptoms. For this
infection, a wide variety of antibiotics may be
prescribed.
Infections by Escherichia coli and other
bacteria living in human intestines cause a great deal of
diarrheal illness in American children. These infections are also
prevalent among travelers to other countries--particularly those
visiting Mexico, South America, and Southeast Asia. People with
mild infections recover easily. Those with severe infections,
however, require prompt fluid and electrolyte replacement to
prevent fatal dehydration. This cautious course is especially
important for children, who are highly susceptible to
dehydration.
Symptoms include the sudden onset of watery
diarrhea, abdominal pain, and cramping. Some forms may produce
chills, along with blood and pus in the stools. In small
children, the stools may be yellow or green, and the child may
experience vomiting, irritability, loss of appetite, and
listlessness, possibly progressing to severe dehydration, fever,
and shock.
Treatment includes rest and correction of fluid
and electrolyte imbalances. Intravenous antibiotics are
occasionally needed to treat infections in infants.
Lyme
disease
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Lyme disease is contracted from the bite of an
infected deer tick. A red, enlarging ring is the first sign of
infection. This mark may be itchy, but usually causes no
irritation. Several days later, a few more lesions may turn up.
The blotches last several weeks, and within a few days of their
appearance may be joined by a variety of other symptoms including
stiff neck, malaise, fatigue, chills, fever, headache, achiness,
and muscle pain. Stage two occurs weeks or months later and may
include cardiac and neurologic symptoms such as facial palsy.
These symptoms may last for months or become chronic. Stage three
can begin weeks or years later and is marked by chronic
arthritis-like symptoms.
Early treatment may prevent later complications.
The usual treatment for adults is a 10- to 20-day course of oral
doxycycline or tetracycline, although penicillin, amoxicillin, or
cephalosporins may be used instead. Children under eight years of
age usually receive oral penicillin or amoxicillin. In advanced
stages of the disease, intravenous penicillin or ceftriaxone may
be given for two to four weeks.
The list of infectious diseases goes
on--diphtheria, listeriosis, botulism, gas gangrene,
actinomycosis, dysentery, cholera, poliomyelitis, Colorado tick
fever, Rocky Mountain spotted fever, malaria, giardiasis,
trichinosis, hookworm--but, happily, most are either rare in this
country or easily preventable. If we take full advantage of the
immunization measures and advanced antibiotics available today,
we now have less to fear than ever before in
history.
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